Recently, β-glucan (β-1, 3-1, 6-glucan) attracts attention due to its immunopotentiating effects. That is, β-glucan serves to activate macrophages, NK cells, T cells, killer T cells and the like that attack infected cells and cancer cells in the body, and exhibits effects of eliminating bacteria and foreign matter that have entered the body and suppressing the onset of disease by increasing immunity and resistance. Also, it has been reported that as a result of exhibiting these effects, β-glucan has functions such as suppressing allergies, suppressing malignant tumors such as cancer, reducing blood sugar levels, promoting urination, adjusting blood pressure, and reducing blood cholesterol levels and neutral lipid levels.
As methods for producing β-glucan, a method for extracting β-glucan from baker's yeasts and mushrooms, and a method in which black yeast (Aureobasidium pullulans) is cultured to accumulate β-glucan in the culture medium, are used. It is considered that β-glucan derived from black yeast has higher water solubility than β-glucan derived from other organisms, and has the advantage of being highly effective due to its molecular structure in which the 1.6 chain is densely branched.
The immunopotentiating effects of lactic acid bacteria and of lactic acid-producing bacteria belonging to the genus Bacillus have already been known, and there are many reports thereupon. It is known that these bacteria producing lactic acid have relatively many specific base sequences (DNA fragments) called CpG motifs as components of their cell walls. It is conceivable that the CpG motifs directly stimulate the immune system of mammals to activate macrophages, NK cells, T cells, killer T cells and the like, and to enhance their defense systems against various types of infections.
It should be noted that the term “lactic acid bacteria” is not a bacterial name that is mycologically defined, and its definition is derived from the application of the family name Lactobacteriaceae to gram-positive bacilli and cocci that ferment sugar to produce only lactic acid or to produce lactic acid, acetic acid, alcohol, and carbonic acid gas.
Moreover, lactic acid-producing bacteria belonging to the genus Bacillus are sometimes called spore-forming lactic acid bacteria, but are not classified as common lactic acid bacteria.
Physiologically active effects of Bacillus coagulans have also been widely known, and its usefulness in probiotics has been found. Moreover, the safety of this bacterial strain is also as widely recognized as the safety of common lactic acid bacteria is (Non-Patent Documents 1 and 2).
A finished product in which β-glucan and lactic acid bacteria are mixed in a combination has been developed, and it is reported that in particular, a composition in which β-glucan and Enterococcus faecalis, which is a lactic acid coccus, are combined exhibits effects for enhancing immunity to influenza and preventing the exacerbation thereof (Patent Document 1).